According to Steve Corkran of the Bay Area News Group, Hayden underwent a surgical procedure to clear out abdominal scar tissue.

Perhaps the most important bit of news came from the Los Angeles Times' Sam Farmer, who mentioned that the operation was unrelated to the previous heart injury and subsequent surgery that almost took Hayden's life.

Sam Farmer @LATimesfarmer

DJ Hayden's doctor in Houston tells me it's his understanding this is not related to heart issue. Raiders say he had scar tissue removed.

Though precise medical details are unavailable to the public, speculation suggests Hayden's most recent concern stems from an unavoidable complication of abdominal surgery: adhesions.

What are adhesions? First, let's review Hayden's injury and medical path so far.

As NFL.com's Andrea Kremer wrote in April, concern over internal bleeding forced doctors to cut into Hayden's abdomen to look for the source, as when bleeding is extensive enough, direct visualization is sometimes the only way to determine from where the bleeding is coming.

Surgeons eventually found the source—in his chest, not his abdomen.

The tackle tore Hayden's inferior vena cava (IVC)—the largest vein in the body responsible for bringing blood from the lower body back to the heart. Surgeons repaired the tear, and the rest is history.

Regardless, that need to look inside Hayden's abdomen probably led to Tuesday's news.

When surgeons cut into Hayden's abdominal cavity, they passed through several layers of connective tissue, muscles and the tissue layer making up the abdominal cavity itself—called the peritoneum. Within the peritoneum are the intestines, spleen, liver and other organs.

The intestines are quite mobile and constantly in motion within the abdomen. Under normal circumstances, they and other organs smoothly glide over and around each other without much difficulty.

However, any abdominal surgery—and not just one as extensive as Hayden's—interrupts the normal dynamic of the gut.

To heal and reinforce the layers of tissue and muscle through which the surgeons cut, the body forms scar tissue. Scar tissue is relatively rough compared to healthy tissue and organs.

Additionally, as doctors searched for the bleed, they moved around Hayden's intestines and other organs. Doing so mildly injures the outer layers of affected areas.

As Hayden healed following surgery, his body scarred over the incisions and healed any small trauma to his organs and intestines, as it should.

Unfortunately, previously damaged tissue is never quite the same, and the rough edges of healed-but-scarred tissue can serve as attachment points for otherwise mobile tissues. Scar tissue can build up and connect two damaged areas.

For example, two areas of damaged intestine or other organs can heal "onto" each other. Additionally, one area of intestine can attach itself to scars on the inside of the abdominal wall. Either case constitutes an "adhesion."

Even with the best surgeons practicing the best medicine—as is the case with Hayden—adhesions occur silently following the vast majority of abdominal surgeries.

Regrettably, in a minority of cases, they can also become symptomatic.

If an adhesion is extensive enough and involves the intestines—either attaching to each other or to the abdominal wall—it can disrupt normal flow of food in the gut.

For example, adhesions causing kinks or tangles in the intestinal tube limit stomach mobility and can drastically slow the normal digestive process. They can even block the pathway altogether. Such blockages can result in severe, debilitating abdominal pain—not to mention bloating, vomiting and many other symptoms.

In the worst-case scenario—and there is no reason to believe this occurred with Hayden—prolonged complete blockage can cause intestinal perforation, a life-threatening condition.

Again, details are unavailable, but Hayden himself stated his stomach was bothering him last week, further suggesting the condition.

To correct the problem, doctors usually perform another abdominal surgery. This time, though, the surgery is "laparoscopic," if at all possible. In other words, doctors insert a tiny camera and other small tools through approximately one-inch incisions in the abdomen.

During surgery, surgeons use the camera to directly visualize the adhesions—long, thin strands of pale, tan tissue connecting one organ or tissue layer to another—and cut or cauterize them away.

Once doctors fully resect the adhesions, the intestines resume normal function over a period of a few days to a week. Similarly, the symptoms subside, and the vast majority of healthy patients resume normal activities relatively soon thereafter.

In rare cases, treated adhesions can reform—even years later. Similarly, new adhesions from the first surgery can arise.

What's more, adhesions can beget further adhesions.

The introduction of new incisions to treat the first round of adhesions can also produce more adhesions down the road. For that reason, it is possible Hayden's surgeons elected to use the previous incision site as a route of access this time around.

All of that said, statistically, the above scenarios are much less likely to reoccur. However, Hayden has a few factors working against him.

First off, the size of his original incision is quite large. Furthermore, doctors likely extensively manipulated his gut and other organs in an attempt to locate the bleed.

Despite those factors, the most important takeaway of today's news is that the recent procedure is not directly related to Hayden's heart and inferior vena cava. It does not imply further injury, nor does it increase risk of a similar injury in the future.

Rather, it is merely a downstream consequence of the lifesaving interventions performed by the heroes at Memorial Hermann Texas Trauma Institute.

As long as no unforeseen complications arise, the procedure should only minimally affect Hayden going forward, and Raider fans need not worry. He should fully recover within a month to a six weeks, though the Raiders may hold him out a bit longer given his history.

After all, statistically, this is just a bit of bad luck more than anything else.

Dave Siebert is a medical writer for Bleacher Report, who will join the University of Washington as a resident physician in June. Medical information discussed above is based on his own knowledge and experience, and he has assisted on several laparoscopic abdominal surgeries and adhesion resections.